I wanted to point to a couple of other points in the study that I thought were fascinating. First, the maternal DNA is specifically from Southern Europe, the Northern Mediterranean, and possibly even more specifically Italy. That accords beautifully with several Jewish European origin myths, like the famous Four Captives from Bari (Southern Italy) who established Torah learning in North Africa, Egypt and Spain, or Megillat Ahimaatz. The Kalonymides of the Rhineland traced their lineage to Northern Italy (Lucca). The researchers even suggest that the Jews of Spain and their exiled descendants the Sefardim shared this common origin with the Ashkenazim.
Having written my dissertation on the rabbinic literature of Southern France, I was drawn to the ambiguity of that term, Northern Mediterranean, which might mean specifically Italy and might also mean other areas, like the French Midi. Yaakov Sussman has written a speculative article pointing to a variety of cultural parallels between the medieval Jewish communities of Germany and Provence, and seems to imply that they shared a common source, perhaps in early medieval Italy. This might strengthen that suggestion.
Another point worth noting is the chronology. The researchers have developed a calculator for determining how long ago these genetic events took place. Using it with this data, they say that "these ancestral Jewish populations... may have had an origin in the first millenium BCE, rather than in the wake of the destruction of the Jerusalem Temple in 70 CE".
Some researchers have argued with vigour that the rabbinic Judaism really only spread to Mediterranean Europe in the early Middle Ages, by which time the Hellenized Jews who lived there during Roman times had disappeared one way or another. These new findings seems to suggest that there was continuity from a very early stage.
In his recent lecture, Prof. Haym Soloveitchik emphasized that his search for the origins of the Ashkenazic community is about "culture and not genetics". I think I would go with that.